Major improvement to SpecConstr

[ghc-hetmet.git] / compiler / coreSyn / CoreSubst.lhs

diff --git a/compiler/coreSyn/CoreSubst.lhs b/compiler/coreSyn/CoreSubst.lhs
index 321ea8f..6a2255c 100644 (file)
--- a/compiler/coreSyn/CoreSubst.lhs
+++ b/compiler/coreSyn/CoreSubst.lhs
@@ -16,7 +16,8 @@ module CoreSubst (
 
        emptySubst, mkEmptySubst, mkSubst, substInScope, isEmptySubst, 
        extendIdSubst, extendIdSubstList, extendTvSubst, extendTvSubstList,
-       extendInScope, extendInScopeIds,
+       extendSubstList, zapSubstEnv,
+       extendInScope, extendInScopeList, extendInScopeIds, 
        isInScope,
 
        -- Binders
@@ -56,6 +57,7 @@ import FastTypes
 \begin{code}
 data Subst 
   = Subst InScopeSet   -- Variables in in scope (both Ids and TyVars)
+                       -- *after* applying the substitution
          IdSubstEnv    -- Substitution for Ids
          TvSubstEnv    -- Substitution for TyVars
 
@@ -144,8 +146,8 @@ mkSubst in_scope tvs ids = Subst in_scope ids tvs
 substInScope :: Subst -> InScopeSet
 substInScope (Subst in_scope _ _) = in_scope
 
--- zapSubstEnv :: Subst -> Subst
--- zapSubstEnv (Subst in_scope _ _) = Subst in_scope emptyVarEnv emptyVarEnv
+zapSubstEnv :: Subst -> Subst
+zapSubstEnv (Subst in_scope _ _) = Subst in_scope emptyVarEnv emptyVarEnv
 
 -- ToDo: add an ASSERT that fvs(subst-result) is already in the in-scope set
 extendIdSubst :: Subst -> Id -> CoreExpr -> Subst
@@ -160,6 +162,14 @@ extendTvSubst (Subst in_scope ids tvs) v r = Subst in_scope ids (extendVarEnv tv
 extendTvSubstList :: Subst -> [(TyVar,Type)] -> Subst
 extendTvSubstList (Subst in_scope ids tvs) prs = Subst in_scope ids (extendVarEnvList tvs prs)
 
+extendSubstList :: Subst -> [(Var,CoreArg)] -> Subst
+extendSubstList subst [] 
+  = subst
+extendSubstList (Subst in_scope ids tvs) ((tv,Type ty):prs)
+  = ASSERT( isTyVar tv ) extendSubstList (Subst in_scope ids (extendVarEnv tvs tv ty)) prs
+extendSubstList (Subst in_scope ids tvs) ((id,expr):prs)
+  = ASSERT( isId id ) extendSubstList (Subst in_scope (extendVarEnv ids id expr) tvs) prs
+
 lookupIdSubst :: Subst -> Id -> CoreExpr
 lookupIdSubst (Subst in_scope ids tvs) v 
   | not (isLocalId v) = Var v
@@ -181,6 +191,11 @@ extendInScope (Subst in_scope ids tvs) v
   = Subst (in_scope `extendInScopeSet` v) 
          (ids `delVarEnv` v) (tvs `delVarEnv` v)
 
+extendInScopeList :: Subst -> [Var] -> Subst
+extendInScopeList (Subst in_scope ids tvs) vs
+  = Subst (in_scope `extendInScopeSetList` vs) 
+         (ids `delVarEnvList` vs) (tvs `delVarEnvList` vs)
+
 extendInScopeIds :: Subst -> [Id] -> Subst
 extendInScopeIds (Subst in_scope ids tvs) vs 
   = Subst (in_scope `extendInScopeSetList` vs)